The logical working-out and disputation of all the implications of an idea can be a long, drawn out process. It can also be difficult to explain to people who haven't followed all the twists and turns of the argument. In this book-length essay, Newman argues that Christian doctrinal "development" is not so much produced by change or innovation, as by unfolding what was already implicit in revelation.
John Henry Newman was an Anglican cleric and one of the chief members of the Oxford Movement. Later, he converted to Catholicism; writing this book was part of the intellectual process which led to this. Newman was eventually allowed to become a Catholic priest (still unusual at the time for Anglican converts); he did so well that he died a Cardinal. His explanations and defenses of Catholic doctrine are still famous. He is currently being considered for beatification.
The concluding chapters of this book are over at Part 2